The present invention relates to a manual call point with a housing base, a cover and an alarm insert comprising a fragile panel, a printed-circuit board, a switching element and an actuating mechanism for the latter.
Manual call points are used, for example, in fire alarm equipment or emergency telephones and are conventionally produced in two designs for direct and indirect actuation. In the alarm type with indirect actuation, the panel is to be smashed and a push button pressed. In the alarm type with direct actuation, which is substantially more common nowadays, when the panel is smashed a spring button jumps out as a result of spring pressure and in the process actuates a switch button of the switching element.
In a known manual call point of the latter type with a bevelled switching gate, the spring button is extended by a resilient rod which rests on the glass panel and holds the spring button in the pressed-down position, so the switch button is held in the ready position. To sound the alarm when the panel is smashed, the spring button is pressed out by the compression spring and the switch button is released to trigger the alarm signal. This embodiment is very expensive from a mechanical point of view, in particular due to the configuration of the spring button with the resilient rod. Moreover, relatively narrow tolerances must be adhered to, and therefore this embodiment is costly to produce.
EP-A-0 592 925 describes a manual call point in which the spring button is fastened to an operating lever and together therewith is pressed by a compression spring against the glass panel. The operating lever is rotatably fixed at one end and at the other end has a resilient element which presses on a switch button when the glass panel is smashed. In this manual call point the switch button is not in the ready position in the normal state, so it is not possible to control precise functioning of the alarm from the control center. Instead, each alarm must be controlled in situ which certainly does not simplify the operation and service of an alarm system equipped with these alarms. Furthermore, the construction of the manual call point and its actuating mechanism formed from the operating lever, the spring button, the compression spring and the resilient element are not optimal from the point of view of economical manufacture.
The present invention provides a manual call point of the type mentioned at the outset, the capacity to function and readiness of which can be monitored from the control center, and which has a simple construction and can be produced economically. Accordingly, the operating mechanism for the switching element is formed by a pivoting lever resting on a lateral edge of a panel, which in the normal operating state of the manual call point presses on the switching element and holds this in a closed position.
In a preferred embodiment of the manual call point according to the present invention, when the panel is smashed, the pivoting lever pivots which opens the switching element which in the normal state is always switched on and can therefore easily be monitored in terms of its capacity to function from a control center. Use of the pivoting member as an actuating mechanism simplifies this enormously, so both the material and the production costs are considerably reduced.
In another preferred embodiment of the present invention, the switching element is arranged on a printed-circuit board. This arrangement contributes to a reduction in the production costs since the switching element is applied to the printed-circuit board when it is fitted, thereby eliminating expensive subsequent installations.
Yet another preferred embodiment of the manual call point according to the present invention the pivoting lever is designed with two arms. One end rests on the panel and the other end presses on the switching element which preferably has a sprung end switch. In this configuration, with the pivoting lever being arranged on the edge of the panel makes the actuating mechanism very strong with regard to tolerance differences, dust and other potential sources of disturbance.
In a further preferred embodiment of the present invention, a device is provided to trigger a test alarm. This device comprises a switching lever to displace the panel until the pivoting lever is released, and a key to actuate the switching lever.
In still another preferred embodiment of the present invention the aforesaid key can be inserted into the alarm from below such that in a first insertion position of the key the switching lever is unlocked, and upon further insertion of the key into a second insertion position the panel is displaced. The switching lever preferably has a positioning digit which in the locked position of the switching lever rests on the adjacent lateral edge of the panel, and upon further insertion of the key moves away from said lateral edge, pivoting the panel and releasing the pivotal lever.